Portable through-the-earth radio

Abstract

The present invention provides an apparatus for portable through-the-earth radio (PTTER). The PTTER provides bidirectional voice and / or data communication between a surface radio and a portable radio. The PTTER also provides a transmit antenna having a primary loop and one or more secondary loops configured to increase the magnetic field produced by the primary loop. The PTTER also provides a transportable loop antenna that can be wound around a form for transportation. The PTTER also provides a receive antenna optimal for implementing noise cancellation. The PTTER also provides a navigation subsystem for detecting distance and direction to increase the effective range of the PTTER. The PTTER can be implemented in a backpack form factor.

Description

FIELD OF THE INVENTION[0001]The present invention relates generally to a radio operable to transmit and receive a signal through the earth or other thick, solid barriers. The present invention relates more specifically to a portable radio operable to transmit and receive a signal through the earth or other thick, solid barriers.BACKGROUND OF THE INVENTION[0002]It is known that most current wireless communication technologies are unable to traverse a thick solid barrier made from materials such as rock, concrete or soil. At frequencies greater than a few kHz, the skin depth of these weakly conductive materials is quite small and electromagnetic waves are attenuated to the point where communication is not possible over even short distances (<1 m). In work environments such as tunnels and mines, workers are therefore not able to readily communicate, for example, with supervisors or other workers located at a different part of the tunnel or located above the surface of the earth.[000...

AI Technical Summary

Benefits of technology

[0029]In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

Problems solved by technology

It is known that most current wireless communication technologies are unable to traverse a thick solid barrier made from materials such as rock, concrete or soil.

In work environments such as tunnels and mines, workers are therefore not able to readily communicate, for example, with supervisors or other workers located at a different part of the tunnel or located above the surface of the earth.

Such communication systems are not only useful for regular day-to-day work; they are indispensable in times of emergency.

However, this clearly restricts the worker to either the length of the wire or requires the worker be in a specific location, the terminating end of the wire, to initiate communication.

It is also expensive to lay sufficient wire, particularly for very long tunnels and mines.

Furthermore, in times of emergency, particularly a mine collapse or similar event, or even just due to wear and tear, wires are prone to sever, rendering the medium unusable.

However, inherent in their designs is a requirement for relatively large and heavy equipment.

The power supply for these devices is thus generally relatively large and heavy.

It is not generally possible for a worker to carry or easily move such a device if it were to have a transmitter.

The size of the antenna further prevents adapting these patents for mobile use.

It is also very difficult to transmit a voice signal at such low frequencies.

The repeaters are in fixed location in the underground environment representing a large investment in infrastructure which may not be practical in underground environments that are only accessed occasionally, such as pipe-lines and sewers.

In the event of an emergency, however, any or all of the repeaters could be damaged or even destroyed.

Similarly, if the repeaters go out of service, the portable units are useless.

In case of a cave or in a tunnel, the high frequency wireless communications between the repeaters and portable units would not work, as they would have to travel through rock.

Additionally, similar to the fixed applications, these repeaters would also require large and heavy power supplies and are therefore not adaptable to portability.

Rhodes proposes the use of simple loop antennas for transmitting, such that there is no new solution to the problems of power consumption and antenna size.

This is not practical for portable, or even fixed, equipment, as is used in an underground environment.

This does not address the problem of saturation of the core, which will occur at the levels of flux density needed to transmit over a useful distances, and is indeed the reason why this type of antenna has to date only been used as a receive antenna in TTE or other applications.

However with this arrangement it is apparent that for a given Dipole Moment the power consumption of an antenna is increased in proportion to the number of arrays used to form the antenna.

However for a portable device used in above and below ground environments, the dielectric medium is air, and this requires the generation of a very high alternating voltage Which may create safety hazards in a unit that is worn on the body, as well as requiring a separate transmitter circuit.

The embodiments described have a number of practical disadvantages including restriction of the user's movements, stress imposed on the antenna windings by said movements, and the exposure of the user to the full strength of the magnetic field created by the loop antenna.

The primary challenge in providing such a technology is the minimization of the size and weight of the equipment, particularly for the transmitter and transmit antenna, to provide portability.

These have not been achieved to date.

Images